Street Epistemology - Practice

[Abaddon_ire]

As to your question about the quality and quantity of evidence.  I think that the evidence needs to sufficient to make evident what is being claimed, and overcome any evidence against it.
For example, in your case of bigfoot, while an a hair/poop sample, which cannot be identified, is supportive towards other evidence of bigfoot, I don't think they would be sufficient on their own.  In the case of drinking water, and curing cancer.  A simple observation is good enough to verify that she drank water.  A doctors examination would be required to declare the cancer as gone.  However, for the correlation between the two, I think more of a study needs to be made to show causation.

I do think that it is difficult to make an exact rule/ formula, as there can be a number of different things to weigh and consider (I don't see us replacing juries with a computer that you just import the information too).  However I wouldn't describe it as arbitrary either.  I have thought about and made a couple of threads here before, about extraordinary claims.  I don't see any justification in making a distinction.  I find that often those who shout extraordinary claims are subjective, ill defined, and a lazy/ poor justification to not deal with the evidence and facts of the matter. 

This is an important point.

Hypothetically, if you were to claim you had a pet dog, I would take you at your word. Plenty of people do, it is pretty commonplace.

If you claimed to have a pet zebra, that might prompt a few follow on questions since, while possible, it would be unusual.

OTOH, if you claimed to have a pet unicorn then I would require a much higher evidential bar to be set.